Dependency Injection
In most real-world projects, we do not instantiate any objects using the new
instance in any of the Controllers, the reason being that we don't want to have tight coupling between the dependent components (between the Controller and the repository). Instead, we pass an interface to the Controller, and the Dependency Injection container (such as Unity) will create an object for us when it is needed for the Controller. This design pattern is commonly referred to as Inversion of Control.
Let's say that a class by the name of ClassA uses another class, ClassB. In this case, it is enough for ClassA to know about the behavior, methods, and properties of ClassB, and it doesn't need the internal implementation details of ClassB. So, we can abstract ClassB and make an interface out of the class, and then have that interface as the parameter instead of the concrete class. The advantage of this approach is that we can pass any class at runtime as long as it...